Seasonal changing use of the surface layer by Arctic zooplankton

• Main Authors: Cornils, Astrid, Flores, Hauke, Wermeyer, Kim, Katlein, Christian, Ashjian, Carin, Campbell, Robert, Castellani, Giulia, Gelfman, Celia, Hildebrandt, Nicole, Serdar, Sakinan, Schmidt, Katrin, Schaafsma, Fokje, Shoemaker, Katyanne, Niehoff, Barbara, Team ECO,, Team ICE
• Format: Conference Object
• Language: unknown
• Published: 2022
• Subjects: Arctic; Arctic Ocean; polar night; Sea ice; Zooplankton
• Online Access: https://epic.awi.de/id/eprint/56477/; https://hdl.handle.net/10013/epic.5a6a95df-b082-4749-84ec-e0ef5bf438e7

Less and thinner sea ice characterizes the new Arctic, but our knowledge on zooplankton dynamics in relation to sea ice conditions in the Central Arctic Ocean is scarce, especially during the Polar night. To investigate the seasonal dynamics of the interaction of zooplankton and sea ice, we sampled zooplankton with a net (150 µm mesh, opening 0.24 m2) attached to a Remotely Operating Vehicle (ROV-net). In approximately weekly intervals, we conducted horizontal tows at the ice-water interface and at 10 m under the ice and occasionally also in > 20m. Once each in summer and in winter, we sampled over 24-hours to investigate the diel variability of zooplankton distribution. All net samples were preserved in 4% formalin onboard. At AWI, they were size-fractionated, split into aliquots and scanned with the ZooScan, yielding >200k of images presenting single objects. These images were uploaded to the web-based application EcoTaxa and classified according to taxonomical criteria. Here, we will present the zooplankton species composition and abundances under the MOSAiC ice-floe, and we will discuss the importance of sea-ice for zooplankton population dynamics.